Process for surfacing sheet material



'FIL-:1.3.1

y 1,610,419 l C. BARQWN Dec. 14 1926.

n PRocEss FOR SURFACING, SHEET MATERIAL Filed August 25 1923 :5sheets-sheet g /NvE/vraf? l' c.BRQwN PROCESS FOR SURFAGING SHEETMATERIAL Filed August 2,3, 1925 3 Sheets-Sheet 5 x @www Patented Dec.14,1926. l 1,610,419 UNITED. STATES PATENT OFFICE.

CHRISTOPHER BROWN, OF CHARLEROI, PENNSYLVANIA, ASSIGNOR TO PITTSBURGHPLATEfGLASS COMPANY, A CORPORATION OF PENNSYLVANIA.

.Pno'cnss non sURFAcINe SHEET MATERIAL. Application mea August 2a,isz-3. `serial No. 658,889.

The invention relates to a process for sur- The tables 1 are providedwith wheels 10 facing sheet material, such as a continuous engaging therails of the -track 2 and in pracribbon of glass, ora seriesof separatesheets' tice these tables are placed end to end and of glass, marble orothermateriahtheA apsuitably coupled together. A continuous 5 paratusbeing here particularly vdescribed uniform movement is given` to thetables to 60 and illustrated as applied to surfacing a carry thembeneath the surfacing machinesv `series of plates of glass. Theinvention has by means of the rack bars 11 secured to the for itsprincipal object the provision of an bottoms offthe cars and driven bythe spur improved straight away system, wherein the gears l12 `which arein, turn driven by suit- 10 time and power required for giving thedeable pinions 13 von driven shafts 14, the 65 siredv finish is reducedto a minimum. In mechanism for driving the shafts 14 not bepracticingthe invention, I make use of the lng shown. The glass is preferablysecured process set forth in my Patent No. 1,480,542. to the uppersurface of the table by means The present invention involves the use ofa of plaster in the usual way, and the spaces plurality of brushesarranged in series in` between the ends of the sheets on the vari-"70termediate a set of grinding machines and a ous cars arel filled withlplaster of Paris so set of polishing machines, the brushes actthat acontinuous, unbroken surface iS preing upon the glass after it issmoothed by sented tothe series o f surfacing machines. i

the grindingv machines. and giving it a The grinding machines comprisesuitable Semi-polish S0 that the Work and power rerunners 15 carried ,byvertical spindles 16 75 quired for the polishing machines isgreatdIlVeIl by elttrlq mOtOIS 17 through the iply reduced. `Byusingthis expedient only termedi'ary of suitable reduction gearingin aboutone half the number of polishing mathe casmg 18. The runners 15; are Of.01'- chjnes, which would yotherwise be required, -dinary constructionhaving cast iron orcast' are necessary,4 One embodiment 0f the in- Steelrunner baIS 011 'their lOWBI faces OI- 80 yention isshownin'theaccompanying drawengagement with the glass, the abrading acin s wherein:1 v j y tion being accomplished, however, by means igure l is a planview of the apparatus,l :ofa mixture of sand and water which is siipFig, 2 is an end elevation of the brushing plied intermediate therunners and the g1ass. 80 mechanism. Fig. 3 is a plan view of theSuitable sand grading apparatus (not e5 brushing mechanism. Fig. 4 is anenlarged 110W11) 1S employed for separating the sand section through aportion of one of the lnto a'series of grades ranging from coarse tbrushes. Fi 5 is an end elevation of one t0 Very ine, andthese gradesareapplied of the grin ing machines.. And Fig, 6 is 1n order, the coarsest abrasive being applied an end elevation of one 'of the polishingmato the first grinders beneath which the glass 90 chines. l passesand-tapering 'off to finer and `liner f In car ing out the invention,the glass .grades astho glass progresses beneath the to be sur aced ismounted upon a series of TUIIIIGTS: The last BW IlDdlDg Immers aretables 1, which is carried along the track 2,' Preferably SUPPlled W11?emely 01 111116111111 40 beneath the `series of grinding machines, whichis somewhat ner thanv the ne sand U5 then beneath a series of brushes 4,and finalld Serves t0 give the glass its final smoothly beneath a seriesof polishing machines 5. lng treatment preliminary to the action. of'The glass with vone side thus finished is thenv the brushes thereon,the term emery being brought back upon the cars to the left hand usedbroadly in the claims to designate both end ofthe track 6 by means of areturn emeryoralundum, the fllSt belng the. Ilt- 10u track and suitabletransfer devices, `.not ural f product and the latter being theartishown, and the glass is reversed upon the taficial product. x 1bles. to bring the u'nsurfaced side up. The The runner spindle in eachgrinding ina- A operation as above described isnow repeat# chine isournaled in 'a suitable-` casing 19 ed, the'tables being carried beneaththeseand this is supported by means. :of a lever i051 ries of grinding"machines 7, the series of 20 P1V0ted at 21 lld'havlng at It?? rear'edbrushes 8 and the polishingy machines 9'. the adjustin rod 22. Thisadjusting rod is The sets of machines above'the two tracks Screw threeed at its' lower end so that the Y 2 land 6 are the same so that adescription of rod may be adjusted vertically to vary the one set willbe sufficient. pressure of the runner upon the glass by ll0- means ofthe hand wheel 23 whose hub is screw threaded internally to engage Vthethreads onA the rod 22. In order to cushion the movements yof therunners, the spring 24: is provi-ded intermediate the hub of the wheel23 and the framework 25. The lower end of the casing 19 isheld inposition by means of the arm 26 havino' a hook at its lower end fittingaround laterally projecting lugs 27 on the casing. The inner end of thelever 20 is similarly releasably connected to the casing by means of itshook shaped ends which engage laterally projecting lugs 28.

The surface ofthe glass is reduced by the. grinding machinesso that itis flat and true corresponding in finish to what is referred. to hasground glass, more. or less cloudy in 'appearance or non-transparent,due to the minute scratches incident to the final finishing with theemery. The next'step in the operation is the reducing of this groundglass surface to a semi-polish so that it has what may' be termed a dullpolish, after which it may be very easily given-a full polish by theregulation polishing machine. The brushes 4 are shown as six 1n number,but this number may be varied depending upon the conditions involving,one consideration being the rate of travel of the glass beneath thebrushes. These brushes are mounted upon suitable shafts 29 carried inbearingsupon the framework 30 and driven by means of direct connectedlmotors 3l arranged as indicated 'in Fig. 3. Any suitable means may beemployed for adjusting the bearings of the rolls or the framework itselfto give the right degree of contact between the brushes and the glassand to compensate for wear in the brushes. v

Each 'brush is preferably constructed as indicated in Fig. 3 having anouter sleeve 32 in which the brush elements 33 are caru securelyclamped'. The brush elements 33 are preferablyr made from wood or Acanefiber,

whi h is relatively hard and tough, in order to secure a maximum wearlngperiod. In

- operation, the brush is preferably run 4at -a speed from one to' -twothousand revolutions per 'minute The degree of pressure between thebrush and the sheet of glass is an important factor in securing a properpolish. In order to secure the best results, the ends of the brush- Aelements should only touch the surface of the sheet lightly, so thatonly theextreme ends ofthe brush elements vstrike the surface yof theglass. The action of the brush elements,

' the ad upon the glass and `each. brush element remained in contacttherewith for a considerin front ofthe first brush and between eachI'Vhen the brush is.

pair of brushes, such mixture spreading out overvthe glass by the timethe brush is reached. The abrasive employed approaches a polishingpowder in fineness, powdered pumice being preferably used, althoughother l `materials might be employed. The smoothing action is apparentlydue to the impact of the particles of abrasive carried by the ends ofthe brush elements upon the glass surface or by the impact of the brushelements upon particles of abrasive which are distributed over thesurface of the glass. By the time the glass passes the last brush, ithas received what may be termed a semi-polish, such polish not beingsuiicient to permit the glass to be used for glazing purposes, but itapproximates this condition-to such an extent that only a limited amountof polishing beneath standard polishing machines employing rouge isrequired.

The polishing machines 5 beneath which the glass passes after thebrushing action are quite similar in construction to the grindingmachines heretofore described except that the runner frame carriespolishing felts instead of grinding runners. As indicated in Fig. 6, therunner frame 35 is carried by a spindle 36 driven from the motor 37 endand carrying the adjusting hand wheel 4l. The lower end of the casmginwhich the runner spindle is mounted is held in position by means of thepivoted arm 424. The runner blocks provided with spindles 43 extendingup through the runner frame 4 35 and carry on their lower sidesvtheusual felts 44 for' engaging the glass. In order to give the necessarypolishing action, a mixture of rougp and water isapplied to the lass,and by t etime the glass has passed om beneath the last polishingmachine, it hasbeen given the necessary degree of finish,

fitting it for glazing or other purposes in which llate glass is used.If it were not for 'tional polishing effect given by the brushes 4,11large number of polimachines would be renired in order to give the`finish, but y the .use 0f the brushes,

I have yfound that the number of machines 1s only a small fraction ofthat required for operating'- the additional polishing machines whichwould be necessary if thebr'ushes were j not used. -The cost ofoperation is, therefore,

substantiall reduced by the use of' the brushes an the length of thesystem is cut down to' a large extent, Ithis bein an importantconsideration because of 51e reat length which is ordinarily required ora straight away system of this kind.

What I claim is:

A process for surfacing a sheet of material, which consists insupporting it an moving it forward horizontally in a right the surfaceuntil a flat smooth surface is secured; second, further abrading thesurface with an abradant of a -finer grade carried over the surface inthe direction of moye-v ment of the sheet,but with'decreased pressureand at an increased speed as compared with the pressure and speed of therst abradant so as to produce a semi-polish; 'and third, polishing thesurface withI rougel applied in a circular direction.

In testimony whereof, I have hereunto subscribed my name Ithis 20th dayof August,

cHRisToPHER BROWN. f

